Integrated phylogenomics and fossil data illuminate the evolution of beetles

Abstract

With over 380,000 described species and possibly several million more yet unnamed, beetles represent the most biodiverse animal order. Recent phylogenomic studies have arrived at considerably incongruent topologies and widely varying estimates of divergence dates for major beetle clades. Here we use a dataset of 68 single-copy nuclear protein coding genes sampling 129 out of the 194 recognized extant families as well as the first comprehensive set of fully-justified fossil calibrations to recover a refined timescale of beetle evolution. Using phylogenetic methods that counter the effects of compositional and rate heterogeneity we recover a topology congruent with morphological studies, which we use, combined with other recent phylogenomic studies, to propose several formal changes in the classification of Coleoptera: Scirtiformia and Scirtoidea sensu nov., Clambiformia ser. nov. and Clamboidea sensu nov., Rhinorhipiformia ser. nov., Byrrhoidea sensu nov., Dryopoidea stat. res., Nosodendriformia ser. nov., and Staphyliniformia sensu nov., alongside changes below the superfamily level. The heterogeneous former superfamily Cucujoidea is divided into three monophyletic groups: Erotyloidea stat. nov., Nitiduloidea stat. nov., and Cucujoidea sensu nov. Our divergence time analysis recovered an evolutionary timescale congruent with the fossil record: a late Carboniferous origin of Coleoptera, a late Paleozoic origin of all modern beetle suborders, and a Triassic-Jurassic origin of most extant families. While fundamental divergences within beetle phylogeny did not coincide with the hypothesis of a Cretaceous Terrestrial Revolution, many polyphagan superfamilies exhibited increases in richness with Cretaceous flowering plants.

New mid-Cretaceous cryptic slime mold beetles and the early evolution of Sphindidae (Coleoptera: Cucujoidea)

“…Historically, Sphindidae, Boganiidae and Cryptophagidae are all placed in the superfamily Cucujoidea. However, recent phylogenetic analyses recovered that this Cucujoidea sensu lato is paraphyletic and contains three separate clades (McKenna et al 2019;Cai et al, 2021). Each of the three families mentioned above is placed in a different clade, and are therefore only distantly related to each other.…”

An aberrant colydiine-like tenebrionoid beetle from mid-Cretaceous Burmese amber (Coleoptera: Tenebrionoidea: Zopheridae)

“…The close relationship between the former Colydiidae and Zopheridae is further supported by molecular evidence (McKenna et al, 2015(McKenna et al, , 2019Cai et al, 2021), while the Monommatidae might be an isolated group (McKenna et al, 2015).…”

“…Tenebrionoidea is one of the largest superfamilies in the beetle suborder Polyphaga, with about 29 families and over 30,000 described species (McKenna et al, 2019;Cai et al, 2021). Tenebrionoids are basically characterised by 5-5-4 tarsal formula in both sexes, femur obliquely attached to trochanter, hind wing with no more than four veins in the medial field, and a tenebrionoid-type aedeagus, although these characters are often secondarily modified in some lineages (Lawrence & Ślipiński, 2013).…”

Prolucanus beipiaoensis gen. et sp. nov.: The First Fossil Species of Lucaninae (Coleoptera: Lucanidae) from the Early Cretaceous of Northeastern China

“…The family Lucanidae Latreille, 1804, is long considered to be one of the earliest diverging lineages of the superfamily Scarabaeoidea Latreille, 1802, and contains more than 110 genera and about 1300 extant species distributed throughout all main zoogeographical regions except Antarctica [1][2][3][4][5][6]. Most adult lucanids display obvious sexual dimorphism.…”